A small, cheap, and low-power mesh-type piezoelectric ultrasonic transducer (MPUT) from a household USB humidifier has been developed as a sonochemiluminescence generator for the first time. The ultrasonication of an MPUT facilitates the generation of reactive oxygen species to trigger sonochemiluminescence. There is no light emission of luminol without sonication. In contrast, the luminescence becomes very intense by ultrasonication using the MPUT and can be readily observed by a smart phone, enabling the visual detection of luminol without adding any coreactants. Interestingly, ascorbic acid, a common chemiluminescence quencher in the literature, increases the sonochemiluminescence in this system. As a result, a sensitive sonochemiluminescence method has been developed for the visual detection of ascorbic acid with a linear range of 1-40 μM and a limit of detection (LOD) of 0.35 μM. Moreover, the visual detection of superoxide dismutase has been achieved on the basis of its quenching effect, which has a linear range of 0.05-2.0 μg/mL and a LOD of 0.018 μg/mL. Because of its advantages of low cost, small size, and low-power consumption, the USB MPUT holds great potential in sonochemiluminescence (SCL) for the development of portable and disposable analysis devices in point-of-care testing and field analysis as well as chemical education.